108 results about "Electromagnetic reflection" patented technology

The present invention comprises systems and methods for cellular, PCS, GPS and / or Bluetooth mobile communication (e.g., a mobile telephone). The systems and methods employ a fully integrated dual band IFA / loop CDMA antenna for cellular and PCS communication. Fully integrating the CDMA antenna within a PWB provides for mitigation of lumped elements to establish dual banding, and can provide for reduced antenna size, device size, cost and interference form a user's hand. The IFA antenna is configured to transmit and receive within the cellular frequency band via a capacitive tap, and the loop antenna is configured to transmit and receive within the PCS frequency band via an impedance matching stub and ground location. The system and methods further employ a firewall to mitigate antenna coupling, and a metal reflector to reduce the electromagnetic reflection, and improve antenna gain and efficiency.

There are provided a soft magnetic material in the form of particles for suppressing occurrence of electromagnetic interference which is capable of exhibiting the suppressing effect in a broad frequency range from a low frequency band to a high frequency band, as well as an electromagnetic interference suppressing sheet using the material. When a conductive magnetic filler prepared by mixing a conductive carbon with soft magnetic particles at a volume ratio of 3 to 10:50 to 70 is highly filled in a sheet material, there can be obtained an electromagnetic interference suppressing sheet which is suitable for high-density mounting to electronic equipments, has an excellent electromagnetic absorption in a near electromagnetic field, and is fully suppressed from undergoing electromagnetic reflection thereon.

An electromagnetic shielding system for shielding a user's head from electromagnetic waves produced from an antenna of a cellular phone. The electromagnetic shielding system includes an expandable shield assembly that includes a base panel and an arm panel pivotally coupled together for providing an expanded area of coverage for a user's head. The base panel is removably mountable to the antenna of a cellular phone. An electromagnetic reflective member is mounted to the shield assembly for shielding a user from the electromagnetic waves. A coupling assembly is removably mountable to and extends between the shield assembly and the antenna of the cellular phone for positioning the expandable shield assembly between a stored position and a shielding position.

A metamaterial pixel providing an electromagnetic emitter and / or en electromagnetic detector operating within a limited bandwidth. The metamaterial pixel is comprised of plasmonic elements arranged within a periodic photonic crystal array providing an electromagnetic emitter and / or an electromagnetic detector adapted in embodiments for operation at selected bandwidths within the wavelength range of visible out to a millimeter. Performance of the pixel in applications is enhanced with nanowires structured to enhance phononic scattering providing a reduction in thermal conductivity. In embodiments multiple pixels are adapted to provide a spectrometer for analyzing thermal radiation or electromagnetic reflection from a remote media. In other embodiments emitter and detector pixels are adapted to provide an absorptive spectrophotometer. In other embodiments one or more of metamaterial pixels are adapted as the transmitter and / or receiver within a communication system. In a preferred embodiment the pixel is fabricated using a silicon SOI starting wafer.

The invention provides a method for simultaneously obtaining the multiple electromagnetic parameters of a multilayer material by measuring for one time; by the experiment measurement of an electromagnetic reflecting angular spectrum of one time, accurate determination simultaneously to the thickness and the refractive index of each layer of a multilayer dielectric material is realized by optimal calculation according to an angle when the reflecting angular spectrum is at minimum reflection (or maximal reflection). In the invention, electromagnetic wave energy entering a certain working frequency of a multilayer material system is transmitted and reflected on each material interface, the reflecting electromagnetic wave energy of an incident surface is received by a measuring receiver. The angle of incident wave and the angle of the receiver are adjusted continuously so as to lead the reflecting energy to reach an extremum. The incident angle is supposed to be a given value, optimal search is carried out to the parameters of multilayer material by utilizing the simulated annealing algorithm, and the result is the result of the detected multiple parameters. The method can be applied in the fields of remote sensing parameter inversion and the measurement of plasma on a laser surface, etc., and also can be popularized to the field of the multiple parameter measurement of acoustical multilayer material, and is characterized by high efficiency and accuracy.

The invention discloses a device and method for testing electromagnetic scattering of a jet pipe cavity of an aeroengine. A device body is wrapped in a pointed-cone-shaped absorbing material to carry out electromagnetic scattering test on the jet pipe cavity, the pointed-cone-shaped absorbing material at the outer wall can absorb most radar waves, electromagnetic wave reflection at the outer wall of a jet pipe model can be effectively shielded during electromagnetic test, electromagnetic reflection at the metal outer wall of the jet pipe model is eliminated, reliable electromagnetic scattering data of the jet pipe cavity is obtained, and the test data can accurately reflect the electromagnetic scattering characteristic of the jet pipe cavity. The test device is simple in structure, low in processing difficulty, low in cost and convenient to operate, can be used repeatedly, and greatly reduces the cost of electromagnetic scattering test of the jet pipe cavity; the test method can be used to obtain accurate and reliable test data; and the test method and device have great significance in researches on electromagnetic scattering of the jet pipe cavity.

The embodiment of the invention provides a positioning method, device and system of a receiving device, a storage medium and an electronic device. The method comprises the following steps of transmitting a pilot signal to an electromagnetic reflecting surface through a transmitting device; regulation and control information being sent to the electromagnetic reflecting surface control unit throughthe transmitting device; wherein the regulation and control information comprises the time sequence information and regulation and the control direction information, the regulation and control information being used for indicating the electromagnetic reflection surface control unit to point a reflection wave beam formed by the target pilot signal on the electromagnetic reflection surface to a preset direction in a target time period, and the preset direction being a direction indicated by preset direction information corresponding to the target time period; and determining a signal measurementresult corresponding to the preset direction through the transmitting device or the receiving device, and positioning the receiving device according to the preset direction and the signal measurementresult. According to the method, a technical problem that the terminal cannot be positioned by utilizing the characteristics of the electromagnetic reflecting surface in the prior art is solved, andthe effect of positioning the terminal by utilizing the characteristics of the electromagnetic reflecting surface is achieved.

A bidirectional wave absorption strong electromagnetic shielding optical window of a multilayer graphene mesh / metal mesh laminated structure belongs to the optical transparent member electromagnetic shielding technology field. The electromagnetic shielding optical window utilizes the different light transmission and microwave shielding characteristics performed by the graphene mesh films when the graphene mesh films have different mesh unit hole area ratios to organically combine the low-reflection and partial absorption microwave characteristics of the graphene mesh films with the strong electromagnetic reflection characteristics of the high-light transmission dual-layer metal meshes, and the multilayer graphene mesh films are placed at the two sides of the dual-layer metal meshes to form a multilayer structure. The dual-layer metal meshes separated by the graphene mesh films are used as the transparent reflection layers, and the graphene mesh films separated by the transparent mediums are used as the transparent absorption layers. By the structure, the radio frequency radiation at the two sides of the optical window can penetrate the absorption layers simultaneously and repeatedly to be absorbed strongly, so that the bidirectional strong shielding and low-reflection characteristics are realized, the visible light has a high light transmission rate by transmitting the laminated structure once. The electromagnetic shielding optical window solves the problem that a conventional transparent electromagnetic shielding method can not consider the bidirectional low-electromagnetic reflection, the strong electromagnetic shielding and the high light transmission simultaneously.

An embodiment of the invention provides a voice coil motor control method and system and a controller. A voice coil motor is electrically connected with a drive circuit and is mechanically connected with a displacement sensor; and the drive circuit and the displacement sensor are electrically connected with the controller. The voice coil motor is subjected to closed-loop control through digital signals, which can be prevented from interference of electromagnetic reflection and mechanical vibration of the voice coil motor, so that reliability is high; and a peripheral circuit is simple.

A method and apparatus for production testing of a device under test (DUT) in a chamber is disclosed, the chamber defining an internal cavity therein, adapted to enclose the DUT, and including walls having inwardly facing surfaces of an electromagnetically reflective material, thereby supporting several resonant modes within the internal cavity. The method comprises: arranging the DUT at one or several measurement position(s) in the internal cavity; measuring radio frequency transmission between the DUT and at least one chamber antenna arranged in the internal cavity sequentially in a number of different static mode distribution configurations; comparing the measured radio frequency transmission at said predetermined mode distribution configurations with reference values obtained from measurement of a reference device arranged at the same measurement position(s) within the internal cavity, and at the same static mode distribution configurations; and determining whether the DUT is acceptable or non-acceptable based on said comparing.

An electromagnetic shielding optical window based on a graphene / transparent conductive film composite structure belongs to the optical transparent member electromagnetic shielding technology field, and organically combines the low-reflection and partial absorption microwave characteristics of the graphene mesh films with the strong electromagnetic reflection characteristics of the high-light transmission conductive films, thereby forming a multilayer structure. The transparent conductive films are used as the transparent reflection layers, and 1-6 layers of graphene films separated by the transparent mediums are used as the transparent absorption layers. By the structure, the radio frequency radiation can penetrate the transparent absorption layers repeatedly to be absorbed strongly, so that the strong electromagnetic shielding and low electromagnetic reflection characteristics are realized, and the visible light has a high light transmission rate by transmitting the multilayer structure once. The electromagnetic shielding optical window of the present invention solves the problem that a conventional transparent electromagnetic shielding method can not consider the low-electromagnetic reflection, the strong electromagnetic shielding and the high light transmission simultaneously, and has the characteristics of high light transmission, strong electromagnetic shielding and low electromagnetic reflection.

The present invention relates to a method of verifying a measurement accuracy of a level gauge system. The method comprises determining a first measurement value indicative of a time-of-flight of a first electromagnetic reflection signal to a reference reflector and back; determining a measurement unit verification measurement value based on a response signal from a verification arrangement; determining a second measurement value indicative of a time-of-flight of a second electromagnetic reflection signal to the reference reflector and back; and determining a verification result based on the first measurement value, the second measurement value and the measurement unit verification measurement value. Through embodiments of the present invention, it will be verified that the measurement unit is functioning correctly and that level gauge system works as it should also after being reconnected to the propagation device.

The invention discloses a nondestructive measurement method for water content of roller-compacted concrete. According to the method, dielectric constants of an upper surface layer and a lower surface layer of the roller-compacted concrete are acquired according to electromagnetic reflection strength, and the water content is calculated on the basis of the dielectric constants. Compared with the prior art, the nondestructive measurement method has the advantages as follows: (1), surface reflection strength of the upper layer and the lower layer of the roller-compacted concrete is measured with a ground penetrating radar technology, the dielectric constants of the upper layer and the lower layer of the concrete are calibrated by means of the reflection strength, and the water content of the upper layer and the lower layer of the concrete is predicated according to the dielectric constants, and the method has the characteristics of rapidness and accuracy and can realize overall control on construction quality of the roller-compacted concrete to the greatest extent; (2), the measurement method has the advantages of high working efficiency, high resolution ratio, nondestructive performance and the like.

The invention, which belongs to the technical field of electromagnetic shielding of an optical transparent element, provides a graphene / double-layer-metal-mesh--included transparent electromagnetic shielding device with a bidirectional wave absorbing effect. The electromagnetic shielding device employs a metal mesh A and a metal mesh B as transparent reflection layers; 1 to 6 layers of graphene films separated by transparent mediums are used as transparent absorption layers A and B; and the transparent absorption layers A and B are arranged at the two sides of transparent reflection layers. On the basis of organic combination of low reflection and partial microwave absorption characteristics of the graphene film with the strong electromagnetic reflection characteristic of the high-light-transmittance dual-layer metal mesh, radio-frequency radiation at two sides of the device can pass through the absorption layers by multiple times and thus can be absorbed strongly to realize bidirectional strong shielding and low reflection characteristics and visible light only passes through the multi-layer structure once to realize high light transmittance. With the electromagnetic shielding device, problems that bidirectional strong electromagnetic shielding, high light transmission and low electromagnetic reflection can not be realized simultaneously by the existing transparent electromagnetic shielding method can be solved; and thus the electromagnetic shielding device has characteristics of bidirectional high light transmittance, strong electromagnetic shielding, and low electromagnetic reflection.

A bidirectional wave absorption transparent electromagnetic shielding device based on graphene / transparent conductive films belongs to the optical transparent member electromagnetic shielding technology field, and is formed by assembling a transparent absorption layer A, a transparent medium A, a transparent reflection layer, a transparent medium B and a transparent absorption layer B which are orderly laminated and parallelly configured. The transparent absorption layers A and B are both formed by 1-6 layers of graphene films separated by transparent mediums, and the transparent reflection layer is composed of transparent conductive films comprising transparent metal compound films, silver nanowire films or metal meshes. The electromagnetic shielding device can absorb the radio frequency radiation at the two sides of the devices simultaneously, repeatedly and strongly, thereby realizing the bidirectional strong shielding and low reflection characteristics. The electromagnetic shielding device of the present invention solves the problem that a conventional transparent electromagnetic shielding method can not consider the bidirectional low-electromagnetic reflection, the strong electromagnetic shielding and the high light transmission simultaneously, and has the characteristics of high light transmission performance, strong electromagnetic shielding and bidirectional low electromagnetic reflection.

Besides a plurality of base stations (64) enabling telephone calls between mobile terminals (30) and between the mobile terminals (30) and fixed telephones (12), a call management apparatus (60) is further provided a broadcasting station (72) that transmits call origination information via a broadcasting station carrier of a frequency band that is lower than that of a telephone call carrier. Furthermore, each mobile terminal (30) is provided with a broadcasting station carrier receiver portion capable of receiving broadcasting station carriers. An exchange control station (70) transmits call origination information from the broadcasting station (72) via a broadcasting station carrier if a mobile terminal (30) is in a state in which it is incapable of transmission / reception via the telephone call carrier. Since broadcasting station carriers have a better electromagnetic reflection characteristic than telephone call carriers, each mobile terminal (30) can receive call origination information by using the broadcasting station carrier receiver portion even if the mobile terminal (30) is in a state in which it is incapable of transmission / reception via the telephone call carrier. Thus, the communication of call origination information to the mobile terminals (30) can be improved.

The invention relates to an electromagnetic solving method for particle launching simulation. The electromagnetic propagation is simulated by the motion of particles, and the density of particles represents electromagnetic energy. Each particle has the attributes of position, velocity, total displacement distance, interval angle, lifetime, existence and the like, and the particles follow the electromagnetic reflection and diffraction laws. In this way, the rendering of particles can be visualized; space can be partitioned according to the required resolution, the number of particles in a grid can be counted, and the electromagnetic energy of the point can be solved; the motion of particles represents the diffusion of irradiation, and the calculation of diffusion factor can be omitted. The electromagnetic solving method has the characteristics of high accuracy, simple and visual method and high degree of parallelism, and can be applicable to various electromagnetic calculation solving and visualization systems.

The invention discloses a novel high-power microwave millimeter wave air-cooling type conical-structured absorption dry load, and belongs to the fields of high-power microwave millimeter wave devices.The structure comprises metal heat conducting sheets and wave-absorbing dielectric sheets which are arranged periodically and alternately; the metal heat conducting sheets and the wave-absorbing dielectric sheets form a columnar structure with a conical cavity in the interior, and the bottom of the conical cavity is connected with circular waveguide; and a layer of slotting heat dissipation sheets are also arranged on the outer side of the columnar structure. The metal heat conducting sheets and the wave-absorbing dielectric sheets are arranged periodically and alternately, so that electromagnetic disturbance in the dry load can be lowered, and the electromagnetic reflection of the dry load is further lowered; by virtue of high microwave attenuation characteristic of the wave-absorbing dielectric, the microwave absorption capability of the dry load is ensured; and by virtue of strong heat conduction of the metal heat conducting sheets, the heat of the wave-absorbing dielectric can beguided to the heat dissipation sheets quickly to lower the internal temperature of the load. The novel high-power microwave millimeter wave air-cooling type conical-structured absorption dry load hasthe advantages of high power capacity, broad working frequency band, high stability, small size, convenience in use, low cost and the like.

The invention discloses an electromagnetic shielding curved-surface optical window based on an ultrathin doped metal / medium composite structure, belonging to the field of electromagnetic shielding of optical transparent parts. According to a curved-surface transparent electromagnetic shielding device in the invention, a dielectric film and an ultrathin metal film are sequentially deposited on a curved-surface substrate to form a composite structure, a high-quality doped metal film with a continuous surface and extremely low roughness is obtained under an ultrathin thickness condition by utilizing a co-doping deposition method, and a novel solution is provided for electromagnetic shielding of a large-size curved-surface light window. The thickness of the ultrathin doped metal film and the dielectric film is less than dozens of nanometers and is far less than the microwave band electromagnetic wave wavelength, so stable strong electromagnetic reflection can be provided, electromagnetic shielding bandwidth is greatly widened, and the problem that the electromagnetic shielding bandwidth of a metal mesh structure is seriously limited due to periodic trepanning is solved. Meanwhile, the light transmittance and the electromagnetic shielding efficiency of the composite structure are controlled by regulating and controlling the number of ultra-thin metal / medium units, and strong electromagnetic shielding in a broadband range is achieved. Furthermore, by designing a combination of the thickness of the ultrathin doped metal and medium units and the number of the units, the coupling transmission of visible light by the composite structure is realized, and good optical permeability is realized.

A radar level gauge system, comprising a transceiver; an antenna arrangement configured to transmit an electromagnetic transmit signal from the transceiver, and to return an electromagnetic reflection signal resulting from reflection of the transmit signal at a surface of the product back towards the transceiver; and processing circuitry. The antenna arrangement comprises: a dielectric antenna body having a transmit signal receiving surface to receive the transmit signal from the transceiver, a convex transmit signal emitting surface configured to direct the transmit signal towards the product following passage of the transmit signal through the dielectric antenna body, and a side surface connecting the transmit signal receiving surface and the transmit signal emitting surface; and an electrically conductive antenna housing covering at least a portion of the side surface of the dielectric antenna body. The dielectric antenna body is arranged to conductively separate the transceiver from the conductive antenna housing.

The invention discloses a preparation method of a wave-absorbing continuous SiCN ceramic fiber. The preparation method comprises S1, adding polycarbosilane crosslinked fibers in a vacuum sintering furnace, and vacuumizing; S2, heating the vacuum sintering furnace, and introducing a mixture of ammonia gas and helium gas; S3, introducing the mixture continuously, and keeping inner pressure of the vacuum sintering furnace unchanged; S4, heating the vacuum sintering furnace continuously, and stopping introducing the mixture into the vacuum sintering furnace; S5, reducing inner pressure of the vacuum sintering furnace, and continuing to heat the vacuum sintering furnace; S6, stopping heating the vacuum sintering furnace, and acquiring the wave-absorbing continuous SiCN ceramic fiber when the temperature of the vacuum sintering furnace drops to 50 DEG C and below. Compared with the prior art, the preparation method of the wave-absorbing continuous SiCN ceramic fiber has the advantages that the technical flow is simple; the prepared wave-absorbing continuous SiCN ceramic fiber has resistivity of 104-108 omega cm, lowest electromagnetic reflection loss of up to -63.7 dB and effective absorption bandwidth of 4.20 GHz; the wave-absorbing continuous SiCN ceramic fiber has high resistivity and excellent wave absorbing performance for X band and Ku band.

An electromagnetic shielding optical window based on a graphene mesh and transparent conductive film laminated structure belongs to the optical transparent member electromagnetic shielding technology field, and utilizes the different light transmission and microwave shielding characteristics performed by the graphene mesh films when the graphene mesh films have different mesh unit hole area ratios to organically combine the low-reflection and partial absorption microwave characteristics of the graphene mesh films with the strong electromagnetic reflection characteristics of the high-light transmission conductive films, thereby forming a multilayer structure. The transparent conductive films are used as the transparent reflection layers, and N layers of graphene mesh films separated by the transparent mediums are used as the transparent absorption layers. By the structure, the radio frequency radiation can penetrate the absorption layers repeatedly to be absorbed strongly, so that the strong shielding and low-reflection characteristics are realized, and the visible light has a high light transmission rate by transmitting the laminated structure once. The graphene mesh films have the periodic hole structures, so that the light transmission performance is improved. The electromagnetic shielding optical window solves the problem that a conventional transparent electromagnetic shielding method can not consider the low-electromagnetic reflection, the strong electromagnetic shielding and the high light transmission simultaneously.

The invention discloses a novel high-power millimeter-wave bipyramidal water load, and belongs to the technical fields of microwave power absorption and measurement. The water load comprises a circular waveguide and a bipyramidal water load, wherein one end of the circular waveguide is connected with the output radiation waveguide of a gyrotron traveling wave tube, and the bipyramidal water load is connected with the other end of the circular waveguide; the bipyramidal water load consists of inner and outer shells with circular bottoms and conical top parts to form a hollow water chamber; and a water outlet is formed in the top of the outer layer conical shell while a water inlet is formed in the circular bottom. By adoption of the novel high-power millimeter-wave bipyramidal water load, electromagnetic reflection in the water load can be effectively reduced, so the design purpose of broadband low reflection is realized; and meanwhile, by virtue of the bipyramidal structure, the volume of the water load is reduced, the water flow speed on the inner wall of the water chamber is improved, and the problem of partial overheat of the water chamber is solved, so that the working performance of the water load can be effectively improved.